Brain Anatomy

Part 2

Brain regions

cerebral hemispheres, diencephalon, brain stem, cerebellum

Cerebral hemisphere

paired superior parts of the brain; most conscious behavior known as the “executive suite”

surface lobes include: frontal, parietal, occipital, and temporal

Frontal lobe

controls voluntary motor functions (right controls left)

Parietal lobe

recieves/interprets impulses for paint, touch, heat, cold, distances, size and shapes

Occipital lobe

controls eye sight

Temporal lobe

auditory and olfaction area

Insula lobe

taste; gustatory

Somatic sensory area

receives impulses from the body’s sensory receptors

Primary motor area

sends impulses to skeletal muscles

Gyri

grooves and ridges

Sulci

furrows or indents

Fissures

deeps grooves divide the cerebrum into lobes

Cerebral cortex

Broca’s area; motor speech area usually in the left hemisphere on top of the cerebrum

Gray matter

outer layer composed of neuron cell bodies

White matter

inner layer made of myelinated fibers

Corpus callosum

connects the left and right hemispheres

Diencephalon

sits on the brain stem, enclosed the cerebral hemispheres, made of thalamus, hypothalamus, and epithalamus

Thalamus

egg-shapes mass of gray matter that surrounds the third ventricle, relay station for sensory impulses passing upward to cerebral cortex, transfers impulses to the correct part of the cortex for localization and interpretation

Hypothalamus

floor of the diencephalon, important autonomic nervous system center, (regulates body temp, regulates water balance, regulates metabolism) houses limbic system to emotions, regulates the pituitary gland, houses mammillary bodies for smell

Epithalamus

forms the roof of the 3rd ventricle, houses the pineal body (endocrine gland) and includes the choroid plexus (forms cerebrospinal fluid)

Brain stem

attaches to spinal cord and made of midbrain, pons, and medulla oblongata

Midbrain

composed of tracts of motor nerve fibers and reflex center for vision and hearing

Pons

bulging center part of the brain stem, bridge between medulla and midbrain, composed of two-way fiber tracts, includes nuclei involved in the respiratory center

Medulla

most inferior part of the brain stem that merges into the spinal cord and contains important centers that control: heart rate, blood pressure, breathing, swallowing, vomiting

Cerebellum

provides involuntary coordination of body movements (balance, muscle tone, muscle coordination) and thin outer gray matter and internal white matter (arbor vitae)